Refractive Surgery in Children

In certain pediatric cases, excimer laser treatment can improve quality of life and prevent permanent vision loss.

By Jonathan C. Song, MD, MBA

Current guidelines for refractive surgery require patients to be at least 18 to 21 years old and to have had a stable refraction for 2 years. This ensures that the eyes have stopped growing and changing and that patients can effectively consent to surgery. There are some exceptions to the rule, however, in situations when laser vision correction (LVC) is medically necessary.

One of the most common reasons for performing LVC in children is anisometropia, which is one of the leading causes of amblyopia in children. There is a risk of permanent vision loss if both eyes do not have equal stimulation during the amblyogenic years, usually up to age 8 and possibly age 12. In very high anisometropia, LVC may be the best way to equalize the refraction in the eyes. Children with high bilateral ametropia (either myopia or hyperopia) that cannot be corrected with glasses or contact lenses are also candidates. LVC is often considered if the patient has developmental problems or neurobehavioral issues that render spectacle or contact lens wear difficult. Left uncorrected, visual impairment can exacerbate behavioral problems and affect the child’s quality of life.

LVC may also be performed to treat high astigmatism following pediatric corneal transplant for congenital corneal opacifications. The excimer laser is an extremely useful tool for treating challenging epithelial conditions with phototherapeutic keratectomy (PTK). In this situation, the laser can be used to treat numerous conditions, such as chronic corneal erosion, irregular corneal surfaces, or anterior corneal scaring.

Research shows that refractive surgery can be safely performed in pediatric pateints;1,2 however, it is important to note that, in all these cases, the aim of surgery is different than when LVC is performed in adult patients. Typically, the goal is to restore binocularity or reduce the refractive error so that the child can function at home and in school. Refractive surgery in children simply to avoid the use of glasses or contact lenses is not indicated due to continued growth of the eye. After correction, we counsel families that corrective eyewear, patching, and/or additional surgery may be needed.

Considerations in Pediatric LVC

Timing is an important consideration. Treating early may offer the best chance of reversing amblyopia, but that must be balanced with the challenges of treating very young children, including cooperation, compliance, and differences in healing response.

Surgeons have to consider what type of refractive surgery to perform, and this may differ from what they would offer an adult patient seeking LVC. In children, performing conventional photorefractive keratectomy (PRK) or surface ablation allows surgeons to avoid haze formation with the use of low-dose mitomycin C. This preserves tissue for future ablation, and avoids a flap that may be more likely to be displaced by a young child.

Often, it is not possible to obtain custom wavefront maps in pediatric patients due to problems with attention, fixation, or sitting still. In these cases, a conventional treatment is used, which has the benefit of a smaller treatment zone and smaller epithelial defect that will heal rapidly, even without a bandage lens.

INDICATIONS FOR CORNEAL REFRACTIVE SURGERY IN CHILDREN

Here is a brief list of conditions that warrant corneal refractive surgery in pediatric patients.

• Severe anisometropia

• High bilateral myopia and difficulty wearing vision correction

• High bilateral hyperopia and difficulty wearing vision correction

• Epithelial dystrophies

There is also the matter of where to perform surgery. Older children may be able to be treated at office-based laser centers. In most cases, pediatric refractive surgery is performed under general anesthesia in a hospital setting. We use laryngeal mask anesthesia and manually hold the eye stable during the procedure. As a precaution, we briefly turn off the gases to the mask before firing the laser to ensure there is no interaction between the laser and the anesthesia gases.

Interesting Cases

A patient that I treated recently was a 5-year-old boy with mental and behavioral issues. He had a 6.0 D power difference between eyes, a degree of anisometropia that leads to severe amblyopia. The mother was very conscientious about patching, but the child would not wear glasses or a contact lens. I performed PRK with mitomycin C on the amblyopic eye. His residual refractive error is now -2.00 D in both eyes, and vision in the amblyopic eye has improved from 20/400 to 20/30.

TO THE POINT

Although many children are not suited for surgical vision correction, some pediatric patients are ideal candidates for refractive surgery.

Another very interesting case is that of a child with epithelial dysplasia, symptoms of which include hair loss, dermatitis, and breakdown of the corneal surface. Due to recurrent corneal erosions, the patient demonstrated severe photophobia. I treated this patient with PTK at about age 7 and again a few years later. Now a young teenager, he continues to have a number of problems associated with his medical condition, but the photophobia has improved and made a meaningful difference in his quality of life.

Not For Everybody, But Still Important

Although excimer laser surgery is generally not indicated for children, it can be a powerful tool for improving vision in situations like those described in this article. It does require cooperation of a pediatric ophthalmologist and a corneal refractive surgeon, and it may involve access to a hospital-based laser. Clinicians who see young patients in their practice with high anisometropia or high refractive errors and who cannot wear spectacles or contact lenses may wish to refer those patients to specialists to see if refractive surgery is warranted.

1. Daoud YJ, Hutchinson A, Wallace DK, et al. Refractive surgery in children: Treatment options, outcomes, and controversies. Am J Ophthalmol. 2009;14794):573-582.

2. Song J, Al-Ghamdi I, Awad A. Pediatric refractive surgery in evolution. Middle East Afr. J Ophthalmol. 2012;19(1):22-23.

Jonathan C. Song, MD, MBA
• Charles C. Manger Chair in Corneal Laser Surgery and associate professor of clinical ophthalmology, University of Southern California Roski Eye Institute, Los Angeles
• financial disclosure: none relevant
jcsong@med.usc.edu